Ree alization and study of a thermal gyroscope based on thermal expansion

This paper presents the study, manufacturing and experimental characterization of a single-axis gas thermal gyroscope without solid proof mass. The working principle of the device is based on the deflection of a laminar gas stream due to the Coriolis effect. Bidirectional gas flow is generated by alternating heat generation in two opposite and resistive microheaters. The thermal expansion gyroscope has a simple structure. Indeed, the device consists of a micomachined cavity on which three bridges are suspended. The central bridge is electrically separated into two segments to obtain the two heating resistors that can be powered separately of each other. Two other bridges placed symmetrically on either side of the central one are temperature detectors. The difference of temperature between these detectors is a function of the rotational velocity applied to the device. Several parameters such as the heaters duty cycle, the nature of the gas and the heating power injected into the heating resistors have been studied in order to define an optimal operation allowing to obtain the best sensitivity over a measuring range of 1080 °/s. The robustness of the device has also been studied and validated for a shock test of 10000 g and a duration of 400 μs.